The invention relates to a safety rail system for installation on buildings, particularly the roofs of buildings. In particular, the invention relates to a safety rail system which can be installed on a sloping roof and which serves as a barrier to prevent, or at least hinder, snow or other debris falling from the roof onto the ground below.
Known roof safety systems comprise a safety rail or track to which a safety rail traveller and associated safety line may be attached. EP 0 593 150 describes a roof safety system in which a rail is provided at the ridge of a pitched roof. A traveller, such as that disclosed in GB 2 328 664 A, is slideably mounted on the rail, so that a person working on either side of the pitched roof can secure a safety line to the traveller for protection from falling off the roof. Although rail and traveller systems provide the advantage of an attachment point which is easily moved to any position along the length of a roof ridge, the prior art roof safety systems require special fixings and are not readily retrofitted to an existing roof.
It is an object of the present invention to provide a rail and traveller safety system which may be readily fitted to an existing roof or other part of a building without the need to replace any part of the roof or building and without the need for special fixings.
According to a first aspect of the present invention there is provided a safety rail system comprising:
a longitudinal base unit of substantially uniform cross section adapted to be fixed to the surface of a building, and
a longitudinal rail unit of substantially uniform cross section adapted to allow the attachment of a safety rail traveller,
wherein the base unit and rail unit are provided with corresponding male and female continuous key portions to permit the base unit and rail unit to interlockingly engage by longitudinal sliding action.
Preferably, the system comprises a plurality of base units and rail units which are interconnected to form a continuous rail. This allows a continuous rail to be formed from short units, typically 2 meters long, which may be readily stored and transported to site. Preferably, the rail unit is of equal length to the base unit. Preferably, the joints between adjacent base units are offset from the joints of adjacent rail units. Offsetting the joints in this way results in a strong composite structure with no planes of weakness, and ensures perfect alignment of adjacent rail units, thus creating a smooth, continuous rail on which the traveller may slide or roll.
Preferably, the base unit is provided with a male key portion adapted to slidingly engage with a female key portion in the rail unit. The rail unit will therefore be restrained from movement relative to the base unit in all degrees of freedom except for the longitudinal direction.
Preferably, crimping is applied to the base unit during installation so that the rail unit is also restrained in the longitudinal direction. Alternatively, adhesive may be applied to the base unit and/or the rail unit.
Preferably, the base unit is secured to a sloping roof. Preferably, the roof is a profiled roof, and has a profiled metal sheet at its outer surface comprising adjacent ridges and valleys extending along the line of maximum slope of the roof. Preferably, the base unit is secured to the roof at the ridges of the metal sheet. In this way the safety rail allows water to pass beneath the base unit along the valleys of the metal sheet, while preventing debris and snow from sliding down the roof.
According to one preferred embodiment each base unit is provided with opposed support flanges adapted to be secured to the adjacent surface of the building. Preferably the support flanges are secured to the adjacent surface of the building using any conventional fastener, such as rivets, toggle bolts or drill-drive fasteners.
According to another preferred embodiment the system further comprises at least one fastening plate adapted to be secured between the base unit and the roof, with each base unit being provided with opposed support flanges adapted to be secured to the fastening plate. The fastening plate may be fixed to the surface of a building in any conventional manner.
Preferably the fastening plate is secured by a fixing to a purlin of the roof. Preferably, the support flanges of the base unit are each provided with a plurality of apertures for connection to corresponding apertures in the fastening plate.
Preferably, the roof safety system includes a plurality of fastening plates. Preferably, the fastening plate has a raised central portion adapted to fit with its lower surface on a ridge of a profiled roof. Preferably, the fastening plate has a lower side portion adapted to locate over a valley of the profiled roof with its upper surface flush with the adjacent ridge of the profiled roof.
According to a second aspect of the present invention there is provided a combined safety rail and retaining rail system comprising:
a longitudinal base unit of substantially uniform cross section adapted to be fixed to a sloping surface of a profiled roof, and
a longitudinal rail unit of substantially uniform cross section adapted to allow the attachment of a safety rail traveller,
wherein the base unit and rail unit are provided with corresponding male and female continuous key portions to permit the base unit and rail unit to interlockingly engage by longitudinal sliding action, wherein the base unit spans between adjacent ridges of the roof, thereby serving as a retaining rail to retain snow and/or debris on said sloping roof while allowing the passage of rain and/or melt water beneath the base unit between adjacent ridges.
The combined safety rail and retaining rail system may comprise one or more features of the safety rail system according to the first aspect.
Preferably, the base units and rail units are made from aluminium, although other materials, including alloys and composites, are envisaged. The base units and rail units may be produced using any known manufacturing process for parts of uniform cross section, such as extrusion for metals or pultrusion for plastics or composites.